Nitride and/or oxynitride luminescent materials are known in the art, including those emitting in the red. US2003094893, for instance, describes an illumination unit having at least one LED as light source, the LED emitting primary radiation in the range from 300 to 570 nm, this radiation being partially or completely converted into longer-wave radiation by phosphors which are exposed to the primary radiation of the LED, in which unit the conversion takes place at least with the aid of a nitride-containing phosphor which emits with a peak emission wavelength at 430 to 670 nm and which originates from the class of the Ce- or Eu-activated nitrides, oxynitrides or sialons.
WO2013175336 describes, amongst others for application in a lighting unit, a phosphor having the formula M1−x−y−zZzAaBbCcDdEeN4−nOn:ESx,REy (I), with M=selected from the group consisting of Ca, Sr, and Ba; Z=selected from the group consisting of monovalent Na, K, and Rb; A=selected from the group consisting of divalent Mg, Mn, Zn, and Cd; B=selected from the group consisting of trivalent B, Al and Ga; C=selected from the group consisting of tetravalent Si, Ge, Ti, and Hf; D=selected from the group consisting of monovalent Li, and Cu; E=selected for the group consisting of P, V, Nb, and Ta; ES=selected from the group consisting of divalent Eu, Sm and Yb; RE=selected from the group consisting of trivalent Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Tm; 0≤x≤0.2; 0≤y≤0.2; 0<x+y≤0.4; 0≤z<1; 0≤n≤0.5; 0≤a≤4 (such as 2≤a≤3); 0≤b≤4; 0≤c≤4; 0≤d≤4; 0≤e≤4; a+b+c+d+e=4; and 2a+3b+4c+d+5e=10−y−n+z.